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G'. B. GRAY, OEOO. vHrgr. GRAY. ExEcuTRlx. POWER ACTUATEO SYSTEM OF mmc CONTROL.

APPLICATll-QN FILED AUG.27|'I914,

Patented June 17, 1919.

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G. B. GRAY, DECD.

HJ. GRAY, EXECUTRIX.

POWER ACTUATED SYSTEM 0F TRAFFIC CONTRGL.

AIFLICATION FILED AUG.2\ 1914.

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('RUSS u WB WIT/VESSES: i /Nl/ENTR .K1 BY m TTUR/VEY G. B. GRAY, DECD.

H. F. GRAY, EXECUTRIX. Powfn ACTU/nen SYSTEM oF III/Imc comm. APPLICATION FILED AuG.27. |914. l ,36,759. Patented June 17, 1919.

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@NITED STATES PATENT OTTIME.

GARDNER B. GRAY, 0F PITTSBURGH, PENNSYLVANIA; HELEN F. GRAY, EXECUTRIX OF SAID GARDNER B. GRAY, DEGEASED, ASSIGNOR, BY4 IVIESNE ASSIGNMENTS, TO A. G. WILLIAMSON, TRUSTEE, 0F PITTSBURGH, PENNSYLVANIA.

POWER-ACTUATED SYS'IEIVI OF TRAFFIC CONTROL.

Specification of Letters Patent. P-Ltngd Jun@ jm', 191% Application filed August 27, 1914. Serial No. 858,801.

To all 'whom t may concer/n:

Be 1t iinown that I, GARDNER B. GRAY, a

citizen of the United States, and a residentof Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Power-Actuated Systems of Traffic Control, of which the following is a specilication.

The present invention relates generally toa power actuated system of traffic control such as railroad signals or switches, and has more particularly reference to means for irnparting an indication to the operator that a cert-ain movement of a traffic controlling appliance such as a signal or switch has taken place, and also to prevent him from making any further movement until the movement in question has been fully and properly performed.

The main object of the invention islto render systems of this character more posi-V tive and reliable in their operation for the purpose of safeguarding traffic as much as possible.

The nature of the power' employed in sys tems of this character is immaterial but in the preferred embodiment here disclosed electric power is utilized throughout. One feature of the invention consistsl in preventing power from reaching the indication means so long as power is flowing to the operating means of the switch, and further, should power improperly reach the indication means before power has been supplied to the operating means of the switch, the controlling means in the tower machine will be locked. So also if power is improperly supplied to the indication means as by a cross in the operating wires extending for instance between the tower machine and the switch machine, the tower machine will either be locked so that the operator cannot actuate the same or else it will not be possible for the switch machine to give an indication in the tower machine when the tower machine is next operated. Another feature of the invention resides in controlling means which transmit. a power impulse to the operatingmeans of the switch,fand means controlled by the operatmg means for transmitting a return impulse to actuate the indication means in the tower machine,

together with means for preventing the passage of any-save the right impulse either to the operating means or for the actuation of the indication means. In the preferred form here disclosed the impulses are electric. The particular means utilized to control the impulses is a circuit closer which controls both the power or operating circuit and the return circuit, which circuit closer is controlled by a polarized relay so arranged that when no power is liowing, when power is flowing to the operating means, or when power is flowing both in the power circuit and in the return circuit, it serves to hold the power' circuit closed and the return cir-cuit open. It is only when selective power is flowing in the return circuit and no power is flowing in the power or operating circuit that the polarized relay causes the circuit closer to close the return circuit at that point and to open the power circuit.

The return circuit in the present instance consists of what is termed a. selective circuit through which the return impulse is transmitted and a local indication or releasing circuit which is closed by the polarized relay when the proper selective return impulse is transmitted. 'Ihe local indication oiircuit is preferably fed from the same source of supply as the one that feeds the power circuit. In the preferred embodiment here shown there is no wire common to the operating and selective circuits.

rI`he means for' producing a return impulse in the present instance takes the form of a permanent magnet generator' under the control of the operating means of the traffic governing appliance.

Another feature of the invention consists in providing a pole changer both in connection with the controlling means in the tower and in connection with the controller actuated by the operating means so that the polarity of the selective return current is reversed twice with each movement. Consequently if the proper sequence of operation is not observed no power will ow to the indication means and hence the controlling means in the Itower machine will not be released. 4 l. I

Other features of constraction,` combina tion of parts and arrangement of elements will appear as the specification proceeds.

The invention is embodied in a concrete and preferred form in the accompanying drawings, in which- Figure 1 is a diagrammatic view of a power ac-tuated system of trafiic control embodying the invention. h

Figs. 2, 3, 4, 5 and 6 are detail views showing stages of operation of the 1nd1- cation means.

Fig. 7 is a detail view of the polarized relay.

Similar' characters of reference indicate corresponding parts in the different views.

In the preferred embodiment herein disclosed the traiiic governing appliance is here a railroad switch, not shown, the operating means of which consist of the motor A and selective differential transmission mechanism B controlled by the reverse and normal magnets C and D. The selective differential transmission mechanism is the same as that shown in Patent No. 1,209,146. 10 is a controller actuated by the movement of the switch operating means through the cam 6 and lever 10. E is the device for generating the return current. All the means so far described are located in the so-called switch machine.

F is a lever in the tower machine and Gf is the controlling means here shown as circuit closers. H is the indication means, I is the polarized relay and J the circuit closer thereof. K is a source of power. All these devices are located in the socalled tower machine.

A movement of the lever F to the left from the position shown in the drawing, Fig. 1, will close the following circuit: battery K, bus bar 50, conductor 51, terminals 35 and circuit closer J, conductor 52, spring 53, contact 54, spring 55, conductor 56, coils 28 of the polarized relay, conductorV 57, spring 58 of controller 10, contact 59, sprino- 60, conductor 61, to reverse magnet C, conductor 62, holding magnet 4 which forms a sustaining means, conductor 63, motor A, common returnoonductor 64, conductor 84, battery K. i The, operating lever F by its movement has been placed in what is called the reverse indication position. That is to say, it has been moved far enough to establish the circuit described'but not far enough to release its interlocking with other levers. The lever F has connected to it in the usual manner, by means of the shaft 125, the indication quadrant 16, and the movement of the lever F is arrested by the indication latch 14 coming in contact with a shoulder 101 on the indication quadrant-see Fig. 4.

' The closing of the circuit by a movement of the lever F into reverse indication position will cause the motor A to be operated and to transmit its movement through the selective differential transmission mechanism B in a well-known manner to the traffic governing appliance to move the same in one direction and will at the same time cause the controller 10 to be moved to the right, Fig.

1, thereby cutting off power from the source rection or the other acco-rding to the direction of rotation imparted to it by the selective differential tansmission mechanism B. Mounted on this shaft 6 is a cam 1S which when the said shaft 6 is turned engages the positioning means or lever 1 pivoted at a point between its ends and the free end of which engages the plunger 9. To the upper end of the plunger 9 is attached a weight 2 having a soft iron armature 3 which, when the lever 1 is moved by the cam 18, is brought into contact with the core of the holding coil 4. Since this holding coil is located in the circuit established by the movementof the lever Fit is energized at this time and will hold the said weight 2 or sustain it in its uppermost position so long as current flows. The continued movement of the shaft 6 will eventually release the lever or positioning means 1 and permit its free end to drop back. New when the cont-roller 10 is shifted to the right, Fig. 1, upon the completion of the movement of the traffic controlling appliance or its operating means, the holding coil 4 will become denergized thereby releasing` the weight 2 which will thus be permitted to drop. Pivotally supported on the plunger 9 are two dogs 5. Mounted loosely on the plunger 9 is a sleeve 7 to which is connected the armature 8 of the two coils 11 and 12 and the permanent magnet 21. W'hen the weight 2 therefor descends the dogs 5 will engage the sleeve 7 and will cause a sudden movement of the armature 8 away fromthe coils 11 and 12, thereby generating a current in the said coils which is transmitted back to the tower in a manner to be presently described. Carried by the permalnent magnet are the stops 22 which engage with the projections 100 on the dogs 5 and cause the said dogs to be tilted outwardly thereby disengaging them from the sleeve 7 at the end of the downward movement of the plunger 9. A spring 23 is interposed between the sleeve 7 :and the bridge portion 65 which spring acts to restore the sleeve 7 and the armature 8 to their original position without, however, elevating theJ weight 2.

The current generated by the coils 11 and 12 will now flow along conductor 66, to spring 67, contact 66, spring 69, conductor 70, spring 71, Contact 72, spring 73, conductor 74, through the coils 30 of the polarized relay along conductor 75, spring 76, contact 77 spring 78, conductor 79, spring 80, contact 81, spring` 82, conductor 83, back to coil 11. This impulse from the coils 11 and 12 is selective in that it flows through the polarized relay in a direction opposite to the direction of the power impulse sent to the switch machine with the result that the circuit closer J opens the contact at the points 35 and closes the two contacts marked 36. This completes a localindioation or releasing circuit as follows: from battery K to bus bar 50, conductor 51, points 36 and circuit closer J, conductor 83a, indication magnet 13, conductor 84, back to battery K. The energization of the indication magnet 13 will raise the latch 14 from the position shown in Fig. 4 and will permit the operator to complete the movement of the lever F to the left in Fig. 1, thereby releasing the interlocking between the lever F and other levers in the tower. Since the impulse from the generatorl E is but a momentary one, in consequence of which the local indication circuit is held closed Jfor but a moment, it is necessary to provide means for preventing the latch 14 from dropping back before the operator has had time to complete the movement of the lever F to the left in Fig. 1. This is accomplished by means of the spring S which acts against the pin s and clicks it into a depression X in the latch 14 -when the said latch is elevated by the energization of the indication magnet or releasing means 13. When the lever F is moved back the cam face 15 on the quadrant 16 will restore the latch 14 to its lowermost position by engaging with said latch as shown in Fig. 3.

It it is now desired to move the traffic controlling appliance in the opposite direction the lever F in Fig. 1 is thrown to the right far enough to place it in normal indication position in which position the indication quadrant 16 takes a position opposite to the one shown in Fig. 4. This moves contact 54 into engagement with the springs 85 and 86 thereby establishing the following operating circuit: from battery K, bus bar 50, conductor 51, terminals 35, conductor 52, spring 85, Contact 54,V spring 86, conductor 87, through coils 29 of the polarized relay, conductor 88, spring 89, contact 90, spring 91, conductor 92, normal magnet D, conductor 62, holding coil 4, conductor 63, motor A, conductor 64, conductor 84 back to battery. It will be noted that this impulse passes through the polarized relay in the sameY direction as the impulse established bythe previously described operating circuit. Upon the completion of this circuit the tralic governing appliance will be moved in the proper manner by the selective differential transmission mechanism B and magnet D, and the controller 10 will be moved into the position shown in Fig. 1, thereby cutting otll power from the controlling means. The rotation of the shaft 6 in the opposite direction from that previously described and the denergization of the holding magnet 4 will cause the permanent magnet generator to generate an impulse from the coils 11 and 12, transmitted along conductor 66, to spring 93, contact 81, spring 94, conductor 79, to spring 95, contact 72, spring 96, conductor 74, through coils 30 o polarized relay, conductor 7 5, spring 97, contact 77, spring 98, conductor 70, spring 99, Contact 68, spring 100, conductor 83, coil 11, whereupon the local indication or releasing circuit is again closed and the latch 14 raised as before.

It will be noted that the polarity of the selective return current is reversed by the pole changers 81 and 68 in the switch machine and by the pole changers 72 and 77 in the tower machine. This double reversal of polarity takes place each time so that if the sequence of operation of thc controlling means in the tower machine and the operating means in the switch machine is not adhered to, current will flow through the coils 30 of the polarized relay in the same direction as the direction in which the power current flows through the coils 28 and 2-9 so that the circuit closer J will hold the power circuit closed and the local indication circuit open. In these circumstances the latch 14 will not be released and the operator cannot complete the movement of the lever F and cannot release other levers interlocked therewith.

It will be noted that the present embodiment of this invention requires at least two crosses to produce a false action. Let us assume that two crosses occur, one cross between the wires 64 and 70 and another cross between the wires 88 and 79. Current will now flow from battery K, through bus bar 50, conductor 51, contacts 35, conductor 52, conductor 87, coil 29, conductor 88, through the cross with conductor 79 to conductor 79, conductor 74, coil 30, in a direction opposite to the flow through coil 29, conductor 75, conductor 70 through the cross with conductor 64 to conductor 64, conductor 84, back to battery K. Current from the coils 11 and 12 will tend to flow over the return circuit already traced but this current will be opposed by current from the battery K as follows: battery K, bus bar 50, conductor 51, etc., through 88, through the cross with 79 to 79, thence to 66, coils 12-11, to conductor 83, conductor 70, through the cross with conductor 64, conductor 6,4, conductor 84, and back to battery K. Now it is obvious that while current would How in the right direction the selective circuit, current will also flow in the power circuit and through the relay l in a direction opposite to the direction of the selective current. The circuit closer J would therefore remain in the position which it occupies in the figure and no indication would be given nor would the lever F be released. lilith the lever F occupying a position opposite to the one shown in Fig. 1, let us assume that two crosses occur, one between the conductors 70 and 57 and the other between the conductors 79 and 64. Current will now flow from battery K, through bus bar 50, conductor 51, conductor 52, conductor 5G, coil 2S, conductor 57, through the cross with conductor 70, conductor 70, conductor 74, coil 3() in a direction opposite to the direction of flow through coil 28, conductor 75, conductor 79, through the cross with conductor 6&1, conductor 64;, conductor 84, and back to battery K. The result would be the same as before since current would flow in both directions through the polarized relay and therefore the local indication circuit would not be completed. Thus any cross of the conductors of the selective circuit with the conductors of the operating circuit will prevent any indication.

Now let us assume that there is a cross between the conductor 6-1 and the conductor 70 and that the conductor 79 is crossed with the operating wire of some other lever. Current will flow from battery K, through bus bar 50, wires analogues to 51, 52, S7, and operating wire S8, through the cross with conductor 7 9 to conductor 79, conductor 741,

coil 30, conductor 75, conductor 7 0, throughV the cross with conductor 64C to conductor 611, conductor 84E and back to battery K. Current will now iow in the right direction through the polarized relay and the indication circuit will be closed by the circuit closer J but owing to the fact that the indication quadrant 16 is provided with two notches 37 and 38 the releasing means or indication magnet 13 will now become al locking means or a means whereby the latch 14: is raised into engagement with say the notch 38 thereby preventing any movement of the lever F, see Fig. 6. It follows from this that the selective current must flow at the proper time and in the proper direction and that so long as current is flowing in the operating or power circuit no indication can be given.

The permanent magnet generator E is of advantage because it is under no circumstances in a position to transmit a return im'- pulse until after the movement of the operating means is started, and by reason of the positioning means 1 it is held mechanically inactive practically until the movement of the operating means is completed.

Furthermore it is by reason of the coil l turn supports two soft iron cores 26 each terminating in the adjustableI pole piece 27. Each core carries three coils which are connected into three pairs 2S, 29 and 30, the first two pairs of which are for the power circuit or operating circuit and the latter of which is for the selective circuit. The other pole of the magnet 211 has fastened to it a soft iron pole piece 31 in which is pivoted the soft iron armature 32 at the point cl. One end of the armature 32 swings between the two pole pieces 27, its movement, however, being limited by the stop member consisting of a slotted brass piece 33. Connected to the armature 32 is a brass strip 311 which constitutes the circuit closer J, it being provided at each end with two contacts y' and j only one of each of which is shown. These contacts are opposite the terminals 35 and 36 of each of which there are two but only one of which is shown in Fig. 7

Let us assume that the polarity of the permanent magnet 24: is north at the point where the armature 32 is pivoted and is south at the point where the base 25 is located. The armature 32 will therefore also be of north polarity, while the pole pieces 27 will be of south polarity assuming that no current is lflowing in the coils 28, 29 and 30. The right-hand pole piece 27 is adjusted so as to be closer to 32 than the other pole piece 27 and it is evident that the armature 32 will therefore be attracted to the right. With the parts in this position the contacts y" and the terminals-35 will be normally closed while the contacts j and the terminals 36 will be normally opened. The coils 28 rand 29 are respectively connected into the operating circuits so that when current flows in them 1n the proper direction a magnetic `field will be set up in the direction shown by the arrows. This iield will create a north pole on the left-hand pole piece 27 and a south pole on theright-hand pole Vpiece 27.

Since the polarity of the armature 32 re-V mains unchanged the pull to the right on the armature 32 will be increased and the contacts j and terminals 35 will remain in engagement. y

The coils 30 are so connected into the selective circuit that when current flows in the normal direction for that circuit a magnetic field will be set up in a direction op- -posite to that shown by the arrows. This will cause the right-hand pole piece 27 to become of north polarity and the left-hand pole piece 27 to become of south polarity. The polarity of the armature 32 remaining constantit will now be attracted by the lefthand pole piece 27 and will cause the clisengagement of the contacts 7" with the terminals 35 and cause the contacts j to engage the terminals 36, thereby opening the power circuit and closing the indication circuit. As soon as current in the coil 30 dies out the armature 32 will resume its normal position.

What is claimed, is:

l. A power actuated system of trailic control comprising: traffic governing appliance operating means, controlling means for supplying power to the operating means, means controlled by the operating means for cutting oil' the power supplied by the controlling means, indication means exercising control over the controlling -means, means controlled by the operating means for supplying power to actuate the indication means, and means controlled by the power supplied by the controlling means for preventing power from reaching the indication means so long as poweris flowing to the operating means.

2. A powerv actuated system of tralic control comprising: Vtrailic governing appliance operating means, controlling means for supplying power to the operating means, means controlled by the operating means for cutting olf the power supplied by the controlling means, a latch for locking the controlling means after it is moved into position to supply power to the operating means, releasing means for releasing the latch after power has been applied to the operating means, means controlled by the operating means for supplying power to actuate the releasing means, and means for preventing power from reaching the releasing means so long as power is flowing to the operating means and Jfor preventing the supply o'f power to the operating means while power is being supplied to the releasing means.

3. A power actuated system of trailic control comprising: traiiic governing appliance operating means, controlling means for supplying power to the operating means, means controlled by the operating means for cutting off the power supplied by the controlling means, in dication means exercising control over the controlling means, means controlled by the operating means for supplying power to actuate the indication means, and a polarized relay for preventing power from reaching the indication means so long as power is flowing to the operating means.

4. A power actuated system of traiiic control comprising: trafiic governing appliance operating means, controlling means for sup'- plying power to the operating means, means controlled by the operating means for cutting o the power supplied by the controlling means, a latch for locking the controlling means after it is moved into position to supply power to the operating means, releasing means for releasing the latch after power has been applied to the operating means, means for supplying power to actuate the releasing means, and a polarizedrelay for preventing power from reaching the releasing means so long as power is flowing to the operating means. i Y

5. A power actuated system of traiic control comprising: traiic governing appliance operating means, controlling means and an operating connection for supplying power to actuate the operating means, means controlled by the operating means Jfor cutting oli7 the power supplied by the controlling means, a latch for locking the controlling means after it is moved into position to supply poyver to the operating means, latch releasing means and a power connection therefor, a power connection closer for both the operating connection and the releasing connection adapted to holdthe operating connection closed and the releasing connection open so long as power is flowing to the operating means, and means controlled by the operating means for causing'the power connection closer to close the releasing connection `and to open the operating connection after power ceases to ilow to the operating means.

6. A power actuated system of traffic control comprising: traiiic governing appliance operating means, controlling means for supplying power to the operating means, indication means, or automatically locking Vthe controlling means after, the latter has been moved into position to supply power to the operating means, and Jfor locking the controll-ing means to prevent the supply of power to the operating means if power is supplied to said indication means before the controlling means supplies power to the operating means, and means under the control ol the operating means for supplying power y to the indication means to release the controlling means after the latter has been automatically locked by the said indication means in power supplying position.

7 A power actuated system of trafc control comprising: traiiic governing appliance operating means, controlling means for supplying power to the operating means, means under the control of the operating means for cutting off the power sup-plied by the con` trolling means, a latch for automatically locking the controlling means after it is moved into position to supply power to the operating means, releasing means, controlled by the operating means, for releasing the latch after power is applied to the operating means and for causing the latch to lock the controlling means to prevent the supply of nacer/5s power to the operating means if power is improperly supplied to said releasing means before the controlling means are moved into position to supply power to the operating means.

8. A power actuated system of traiiic control comprising: traiiic governing appliance operating means, controlling means and a power circuit for supplying current to actuate the operating means, means under the control of the operating means for cutting off the current suppplied by the controlling means, a latch for locking the controlling means after it has been moved into position to supply current to the operating means, latch releasing means and a circuit therefor, a vcircuit closer controlling both the power circuit and the releasing circuit and adapted to hold the releasing circuit open and the power circuit closed so long as current is flowingto the operating means, means under the control of the opera-ting means for causing the circuit closer to close the releasing circuit and open the power circuit after cur-l rent has ceased to iiow in the power circuit, said releasing -means acting to cause the latch to lock the controlling means to prevent any opera-tion thereof if the releasing circuit is improperly closed before the controlling means have been moved into position to supply current to the operating means.

9. A- power actuated system oftraiiic control comprising: trailic governing appliance operating means, controlling means for transmitting power of a certain characteris tic tothe operating means, indication means controlling the controlling means, means controlled by the operating means for transmitting power of a diiferent characteristic to control the indication means, and means responsive to and controlled by the transmisison `of power of either characteristic for nullifying the effects of a transmission of power of the other characteristic that is not begun until power of the first characteristic is being transmitted.

10. A power actuated system of trafic contral comprising: traiiic governing appliance operating means, a power circuit connected to the operating means, indication means, a return circuit controlling said indication means, a polarized relay included in said circuits, controlling),` means for transmitting a power-How in one direction through said relay t0 the operating means, means for transmitting a power-fiow in the other direc-- tion through said relay, circuit closers under the control of the relay for preventing the transmission of power in the wrong direction to the operating means or to control the indication means.

11. A power actuated system of traiiic control comprising.: tra'Hic governing appliance operating means, a power circuit, an indication circuit, a control circuit therefor, means controlled by the operating means for producing an impulse in the control circuit, a circuit closer for the power circuit and the control circuit, a polarized relay included both in the power circuit and in the control circuit acting to close the indication circuit and to open the power circuit only when current of a predetermined character is flowing in the control circuit and no current is flowing in the power circuit. Y

12. A power actuated system of trai-llc control comprising: traffic governing appliance operating means, a power circuit, an indication circuit, a control circuit therefor, means controlled by the operating means for producing an impulse in the control circuit, a circuit closer for the power circuit and the control circuit, a polarized relay included both in the power circuit and in the control circuit acting to close the indication circuit and to open the power circuit only when current of a predetermined character is flowing in the control circuit and no current is flowing in the power circuit, controlling means for closing the power circuit at another point, and indication means under the control of the indication circuit for preventing the controlling means from closing the power circuit when current is flowing in the indication circuit.

13. A power actuated system of traliic eontrol comprising: traffic governing appliance operating means, controlling means for transmitting power flowing in a `certain direction to the operating means, a latch for locking the controlling means after it has been positioned to effect the transmission of power tothe operating means, means controlled by the operating means fortransmitting power flowing in a direction opposite to that of the first-named power flow to'effeet the releasing of thel latch, and means responsive to the transmission of power in different directions for preventing the simultaneous operation of the operating means 4and the latch releasing means.

1111. A power actuated system of tra'liic control comprising: traffic governing appliance operating means, controlling means for transmitting a power current flowing in a certain direction to the operating. means, a latch for locking theV controlling means after it has 'been positioned to effect the transmission of current to the operating means, means controlled by the operating means for transmitting a current flowing in a direction opposite to that of thepower current to effect the releasing of the latch, and a polarized relayV controlled yby the power current and the releasing current for preventing releasing` current from-operating said latch while power Vcurrent is flowing and the closing of apower circuit while a releasingcurrent is flowing.

15. A power actuated system of traffic con Lacasse trol comprising: trailic governing appliance operating means, controlling means for supplying power to the operating means, a return connection for transmitting a return impulse produced by the action or the operating means, a reversing means in said return impulse connection actuated by said operating means, a reversing means in the said return impulse connection actuated by said controlling means, indication means con-` trolled by the return impulse, and means for preventing power from reaching the indication means unless both reversing means have been actuated.

16. A power actuated system of tratlic control comprising: trailic governing appliance operating means, controlling means ior supplying power to the operating means, a return circuit for transmitting a return current generated by the action of the operating means, a pole changer for the return current actuated from the operating means, another pole changer for the return current actuated by the controlling means, indication means controlled by the return current, and means for preventing power from reaching the indication means unless both pole changers are actuated in proper sequence.

17. A power actuated system of traffic control comprising: traliie governing appliance operating means, a source of power controlling means for supplying power from said source to the operating means, indication means, a generator, means for actuating the same Jfrom the operating means, and means controlled by the power supplied to said operating means and by said generator for supplying power from said source to actuate the indication means only when no power is being supplied to said operating means.

18. A power actuated system of tratlic control comprising: traffic governing appliance operating means, controlling means for supplying power to the operating means, a permanent magnet generator having a movable armature, an actuating member normally idle for moving said armature away from the permanent magnet, positioning means for said actuating member moved by the operating means, temporary sustaining means for said actuating member ren- CII dered active by power from the controlling means, means actuated by the operating member for cutting ori the power supplied by the controlling means, indication means, and a power connection from the permanent magnet generator for transmitting its impulse to control the indication means.

19. A power actuated system of traiiic control comprising: traffic governing appliance operating means, a circuit including said operating means, controlling means for supplying power to said circuit, a holding magnet included in said circuit, a permanent magnet generator having a movable armature, an actuating member normally idlcior' movin 0' said armature away irom the permanent magnet, positioning means for said actuating member moved by the operating means andserving to move the said actuating member into contact with the holding magnet to be sustained thereby, means actuated by the operating member tor cutting ofi' the power supplied bythe controlling mea-ns so as to denergize the operating means and the holding magnet, indication means, and a power connection from the permanent magnet generator for transmitting the current generated to control the indication means.

Q0. A power actuated system of traflic control comprising: traffic governing appliance operating means, a polarized relay, a circuit closer controlled by the polarized relay, two power circuits passing through the relay and controlled by the circuit closer, a return circuit passing through the relay and also controlled by the circuit closer, controlling means for sending a power flow through either of the power circuits in the same direction thereby causing the relay to hold the circuit closer in position to close power circuits, means under the control ofy the operating means for cutting oit the power supplied by the controlling means, means also under the control of the operating means tor transmitting a return `flow to the return circuit through the relay in a direction opposite to that of the power ilow thereby causing it to move the circuit closer 'to open the power circuits and close the return circuit.

21. A power actuated system or tralic control comprising: traiiic governing appliance operating means, a tower machine, controlling means in the tower machine for transmitting operating current to the operating means, indication means in the tower machine controlling the controlling means, means controlled by the operating means tor producing a return current for the control of the indication means, conductors between the operating means and the tower machine for the operating and the return current, and means whereby a cross between certain conductors prevents actuation et' the indication means and another cross between certain conductors causes the indication means to lock the controlling means.

22. A power actuated system of traiiic control comprising: traiiic governing appliance operating means, controlling means for supplying power to the operating means, means controlled by the operating means for cutting off the power supplied by the controlling means, a latch for locking the controlling means after it is moved into position to supply power to the operating means, releasing means for releasing the latch after power has been applied to the operating means, means oon'trolled by the operating Signed at- Pittsburgli, in tlie county of means for supplying power to actuate the Allegheny and State of Pennsylvania, this releasing means and means controlled by the 25th day of August A. D. 1914.

power supplied by the Controlling means for' GARDNER B. GRAY. preventing power from reaching the indi- Vitnesses:

cation means so long as power is flowing to JOHN T. SwEENEY,

the operating means. GUY P. THURBER.

' Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

